Gallon Environment Letter – the daily edition – a policy letter from the Canadian Institute for Business and the Environment

Public perception of wind speed, and hence of risk, may be flawed

An article in the latest issue of the open access peer-reviewed journal PLOS ONE reports on a study of the public’s perception of risk from high winds compared to the actual risk from such winds. Given that strong winds are likely to become more frequent in the future in most parts of Canada, information on public reaction to strong wind conditions may become a useful tool not only for governments but also for industry and commercial/institutional business operators. For example, if a person is at risk as a result of strong wind, or from their perception of risk from strong wind, while they are on private property other than their own, what steps is it appropriate for the property owner to take to warn the visitor of, and provide them with protection from, the risk?

The research exposed 76 people to winds of 4.5, 8.9, 13.4, 17.9, 22.3, and 26.8 metres per second (10 to 60 miles per hour) in randomized orders and asked them to estimate wind speed and the associated risk to their person. It found that people’s estimates were accurate at lower wind speeds but overestimated at higher wind speeds. People who had previously experienced high wind speeds, for example in tropical storms, were more likely to be accurate in their estimation.

The authors state that the findings have potentially life-saving public policy implications with respect to how information is communicated prior to and during extreme weather events (e.g., tornadoes, hurricanes). Overestimating wind speed may negatively affect people’s decision-making about preparation and evacuation. For example, a major civil problem with government-issued evacuations is the phenomenon of “shadow evacuation,” in which people who do not need to evacuate chose to do so anyway, thereby unnecessarily exacerbating traffic jams along evacuation routes, and filling limited spaces in shelters and hotel rooms. The authors suggest that their findings should be taken into account by policy makers. For example, wind speed forecasts might be accompanied by relevant information such as “this wind speed is sufficient to knock over the average person”.